README update ascii art

README.md

@@ -81,6 +81,8 @@ Example users are in the `vars/secure` directory:
 * [*env_users* for staging environment](/vars/secure/edxapp_stage_users.yml)
 * [*admin_users* will be realized on every server](/vars/secure/users.yml)
 
+
+     ```
      edxapp_prod.yml      <-- example production environment playbook
      edxapp_stage.yml     <-- example stage environment playbook
      edxapp_custom.yml    <-- example custom environment playbook
@@ -96,6 +98,7 @@ Example users are in the `vars/secure` directory:
      │       └── templates
      └── vars             <-- public variable definitions
          └── secure       <-- secure variables (example)
+     ```
 
 
 ### Installation